1. Field of the Invention
The present invention relates to a backlight system, and more particularly relates to a backlight system equipped with several light sources, driven according to the environmental temperature.
2. Description of the Related Art
In a display device, how to start its backlight quickly and make it work constantly are important subjects, and while the display device is applied in vehicle movement, the performance of the backlight will directly influence the drivers' behaviors about driving. But in conventional backlights, light sources of the same kind have always been used and operated in a constant temperature range, hence, when the transport runs into bad weather or under a higher or lower temperature environment, the light sources are often unable to be started or only provide an insufficient brightness. For example, the cold cathode fluorescent lamp (CCFL) is often used as the light source in the conventional backlights, but in a cold weather, this kind of light source is difficult to start, and it must take several minutes to warm up to be bright enough for the operation information being recognized easily.
In addition, the light-emitting diode (LED) is another common kind of light source used in the backlights, but in contrast to the CCFL, the LED is unsuitable for operating in high temperature conditions.
Therefore, even if several light sources are arranged in a backlight, but their lighting efficiency and adaptability to the environmental temperature is undifferentiated. In other words, when one light source is ineffectual in a high or low temperature, other light sources are ineffectual, too. Hence, the motor vehicle driver's safety will be threatened by the arrangement of same kind of light sources in the conventional backlight.